Effect of the grain boundary on the deformation behavior of tungsten bicrystals

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5145940

Fekete, J R

This study is concerned with observations in tungsten, a bcc metal that is elastically isotropic. The goal was to determine the mechanisms of plastic accommodation and use these results to gain insight on the macroscopic deformation behavior. Tungsten bicrystal compression specimens were fabricated from electron beam zone refined tungsten single crystals. The samples had <110> twist boundaries oriented with the grain boundary perpendicular to the compression axis. The misorientation of the samples varied from 8 to 90/sup 0/. After compression, the specimens were analyzed with a variety of techniques. Each technique was selected to observe effects on varying scales of the microstructure. Macroscopic observations confirmed the large effect of plastic anisotropy. Results are explained in terms of the dislocations geometrically necessary for accommodation of the anisotropy, following Ashby. A model is developed that accounts for the lattice rotation at the surface of a specimen in the grain boundary region, as a function of the misorientation and plastic strain level of the bicrystal.

• Research Organization: Michigan Univ., Ann Arbor (USA)
• OSTI ID: 5145940
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals &amp; Alloys-- Structure &amp; Phase Studies
360103* -- Metals &amp; Alloys-- Mechanical Properties
BICRYSTALS
COMPRESSION
CRYSTAL STRUCTURE
CRYSTALS
DEFORMATION
ELEMENTS
GRAIN BOUNDARIES
GRAIN ORIENTATION
METALS
MICROSTRUCTURE
ORIENTATION
POLYCRYSTALS
TRANSITION ELEMENTS
TUNGSTEN